The production of thermoset polymers by the ring-opening or metathesis polymerization of cyclic olefins is well known in the art. Numerous patents and literature references, both U.S. and foreign, relate to the ring-opening polymerization of dicyclopentadiene in the presence of a variety of olefin metathesis catalyst systems. One such catalyst system is disclosed by Sjardijn et al, U.S. Pat. No. 4,810,762, wherein substituted phenolic tungsten halides are employed with triorganotin hydrides. In copending U.S. patent application Ser. No. 278,101, filed Nov. 30, 1988, there is disclosed a catalyst system which comprises a phenol-treated tungsten salt such as the halide or oxyhalide employed with a tin or aluminum compound and a boron halide promoter. Bulk polymerization of dicyclopentadiene in the presence of a catalyst system of this type is illustrated by U.S. Pat. No. 4,729,976.
The ring-opening polymerization of dicyclopentadiene and other cyclic unsaturated compounds finds particular application in reaction injection molding (RIM) processes wherein monomer solutions of the catalyst system components are mixed and injected into a mold where polymerization takes place to form a solid, infusible polymeric product. However, the polymerization of dicyclopentadiene by such a process suffers from several disadvantages. If the polymerization is not virtually quantitative, there will be unreacted monomer in the polymer thermoset product and the molded article will have a most disagreeable dicyclopentadiene odor. This odor greatly limits the applications in which the polymer product can be used. A second difficulty arises from the relatively low and less than desired glass transition temperature for the polymerized dicyclopentadiene product. A typical glass transition temperature (Tg) is in the 130.degree. C.-140.degree. C. range. This glass transition temperature also limits the applications for the polymer product.
It is also known to copolymerize polycyclic polyolefin monomers such as cyclopentadiene trimers, tetramers and higher oligomers with other cycloolefins to obtain higher glass transition temperatures. In European Patent Application 313,838 there is disclosed a process of producing ring-opening polymerization products of higher glass transition temperatures by polymerizing cycloolefin monomers such as norbornene or tetracyclododecene in the presence of from about 5% to about 45% of a resinous cycloolefin formed from cyclopentadiene trimers and higher oligomers which may also contain common unsaturates such as styrene, propylene, butadiene, vinylcyclohexene and isopentene. These resinous cycloolefins are produced by heating dicyclopentadiene in the optional presence of the more common olefin. The polymer products of the European Patent Application have relatively high glass transition temperatures, at times as high as 210.degree. C. or higher, but are difficult to prepare. Lane et al, U.S. Pat. No. 4,899,005, use as feed for a ring-opening polymerization a mixture of polycyclic olefins which may contain small amounts, i.e., less than 20%, of .alpha.-olefins such as 1-hexene, styrene or 4-vinylcyclohexene. A copending U.S. patent application Ser. No. 712,296, now U.S. Pat. No. 5,095,082, filed Jun. 10, 1991, discloses the ring-opening polymerization of mixtures of adducts of 4-vinylcyclohexene and cyclopentadiene in the optional presence of dicyclopentadiene. Numerous other references illustrate ring-opening or metathesis polymerization processes involving other and frequently more complex cycloolefins. It would be of advantage to provide a process for the ring-opening or metathesis polymerization of norbornene-type compounds which is easy and economical to operate and where the products have a relatively high glass transition temperature and no detectable dicyclopentadiene odor.